Hand-held apparatus for spray cryotherapy

ABSTRACT

A self-contained cryotherapy apparatus adapted to be operated with one hand, using flashing temperature of a cartridge liquefied gas (CO 2 ) sprayed in partly solid phase onto the epidermis. The cartridge support and the ejection and expansion system are aligned therewith and in the axis thereof, inside a housing whereof the median part acts as handle to be grasped by the adult user&#39;s hand, whereof the upper part includes an input for inserting the cartridge with its head down and into the housing axis and striking it or for removing it after use, and whereof the lower part includes a calibrated opening forming a passage for the sprayed gas substantially in the housing axis and elements for controlling its effect on the epidermis.

[0001] The invention relates to a self-contained spray cryotherapyapparatus adapted to be manipulated with one hand, particularlyefficient in the treatment of pain, inflammations, or for stimulatingthe circulation: it is well known that cold brings about a vasomotorreflex and an intensification of the action of draining, and evenprocures a muscular relaxation by lowering the muscular tonus: it iswell known that cold makes it possible to obtain a reflex response.

[0002] In this respect, it is recalled that cold is much more efficientthan heat, provided, however, that the treatment is effected with anintense cold which must, in addition, provoke a drop in temperature ofthe zone to be treated in order to take the epidermis from its normaltemperature (about 32° C.) to a temperature included between 2° C. and5° C. where the action of cold is maximum on the cutaneous receptors.Accessorily, it has been observed that the efficiency of the thermalaction of the gas sprayed in liquid phase is further increased in largeproportions by the complementary action of the pressure that the fluxexerts on the epidermis. The majority of cryotherapy apparatus use assource of cold either refrigerated air, or more generally liquidnitrogen whose use remains subject to numerous constraints most oftenlimiting the mobility of the treatment apparatus; in the domain ofsport, where cryotherapy finds one of its major applications, use iscurrently made of small aerosols of gas under low pressure whoseexpansion around a local traumatism produces cold not exceeding −25° C.with insufficient drop in temperature and speed of cooling.

[0003] On the other hand, European Patent EP-0.633.008 in the name ofthe Applicants has already proposed using as source of cold for thecryotherapy, compressed carbonic anhydride (CO2) of which an intrinsiccharacteristic is to procure a flashing temperature of −78° C. atatmospheric pressure. According to the teachings of this Patent, the useof carbonic anhydride in the form of a liquid/vapour mixture makes itpossible to maintain a constant pressure in the recipient during itsemptying; this pressure which is none other than the saturating vapourpressure, depends directly on the temperature of the recipient. Thus, byexpanding to atmospheric pressure, the carbonic anhydride is in twophases: solid and gaseous. It is the solid phase, also called dry ice,which makes it possible to draw off the maximum of calories at the levelof the epidermis of the patient to be treated. In effect, upon itscontact, the solid carbon dioxide, or dry ice, sublimates, thusevacuating a large quantity of heat. It is therefore essential to drawfrom the recipient the liquid phase of the carbonic anhydride in orderto obtain both an intense cold and a temperature drop which is as rapidas possible.

[0004] Patent FR-2.775.589 in the name of the Applicants has alreadyproposed a self-contained, light and portable apparatus capable ofproducing an intense cold procuring a very rapid temperature drop, andthis under maximum conditions of thermal safety using by way ofprincipal the flashing temperature (of the order of −78° C. atatmospheric pressure) of the carbonic anhydride (CO2) or equivalent inliquid/solid phase; to that end, the apparatus comprises a reservoir ofliquefied CO2 under pressure of which the head is connected to a systemof ejection and of expansion of the liquid/solid CO2, and comprisesmembers for controlling the ejection system and for monitoring thetemperature of the zone of use; this apparatus is noteworthy in that thehead of the CO2 reservoir is arranged on the apparatus so that, duringthe whole period of use, only the liquid part of the CO2 inside thereservoir comes into contact with said head in order to be drawn off andpropelled towards the zone of use.

[0005] This apparatus has been designed to be used by professionals,with the drawback that it cannot be used by the individual in a domesticcontext. The present invention therefore relates to an apparatusimproved in order to be used by any adult user simply and without theleast danger occurring in the event of use under poor conditions.

[0006] In this respect, there is proposed, according to the invention, aself-contained cryotherapy apparatus adapted to be manipulated with onehand, using the expansion temperature and pressure of a liquefied gassprayed in at least partially solid phase on a human or animalepidermis, such as CO2 or equivalent, contained under pressure in aremovable cartridge, of which the drawing off head, which is connectedby a support to a controlled system of ejection and of expansion of theliquefied gas, is such that, for the whole duration of a projection,only the liquid part of the gas inside the cartridge comes into contactwith said drawing off head and this apparatus is noteworthy in that thesupport of the cartridge and the controlled ejection and expansionsystem are disposed substantially in line and in the axis of theapparatus, inside an ergonomic housing whose axis corresponds to that ofthe apparatus, of which the median part serves as handle to be graspedby the adult user's hand and comprises a member for controlling thecontrolled gas ejection and expansion system of which the upper partpresents an inlet for introducing into its support the cartridge, headdown and in the axis of the housing, and for striking it or forwithdrawing it after use, and of which the lower part comprises acalibrated opening forming a passage for the sprayed gas substantiallyin the axis of the housing and means for holding the outlet nozzle ofthe controlled ejection and expansion system at the required distancewith respect to the zone of the epidermis to be treated.

[0007] It is therefore question of a light, compact apparatus able tooperate under the conditions of intense cold as recalled in thepreamble, only when it is grasped in the hand and arranged opposite thezone to be treated in virtually vertical position in order to obtain aprojection of gas in liquid phase. In this respect, any other inclinedposition would lead to spraying the gas in gaseous phase, i.e. at atemperature without danger for the user.

[0008] According to several secondary characteristics which will bedetailed hereinbelow, the apparatus according to the invention furthercomprises a certain number of devices guaranteeing the maximum safety ofuse; in particular, it is question of the particular shape of theapparatus which fits perfectly in the palm of a clenched hand, procuringan obligatory position for controlling the projection of the cryogenicline thanks to a double electrical control actuated by two differentfingers of the hand maintaining the apparatus in vertical position; itis also for purposes of safety of use that, according to anotherimportant characteristic of the invention, there is provided a devicefor maintaining the nozzle ejecting the gas at the correct distance inorder that it be absolutely impossible to cool the epidermis in thetreatment zone below a temperature of 2° C., in any case before thecartridge of gas equipping the apparatus is totally empty. Finally, andaccording to a last characteristic, it is provided to complete thepreceding protection systems by temperature sensors procuring within adesired time an alarm for the user and/or interrupting the projection inthe hypothesis of the epidermis being in danger of necrosis, i.e. cooledto below 2° C.

[0009] Other characteristics and advantages will appear more readilyfrom the description of a cryotherapy apparatus according to theinvention for the general public, given hereinbelow by way of preferred,but in no way limiting example, with reference to the accompanyingdrawings, in which:

[0010]FIG. 1 shows a general view of the apparatus according to theinvention maintained vertically in a user's right hand, at the correctdistance from the epidermis to be treated.

[0011]FIG. 2 shows in elevation and in median vertical section theapparatus along line II/II of FIG. 4, showing the internal structure ofthe members as well as their relative position in the apparatus.

[0012]FIG. 3 is a view in elevation and in perspective of the apparatusof which one of the half-shells forming the envelope has been removed inorder to show the internal members represented torn away but in relativeposition of functioning.

[0013]FIG. 4 is a front (proximal) view in elevation of the assembledapparatus.

[0014]FIG. 5 is a rear (distal) view in elevation of the assembledapparatus.

[0015]FIG. 6 is a partial representation on a larger scale of thecryogenic chain showing in detail the drawing off head of a gascartridge mounted on its support inside the apparatus, just before thepercussion of its closure cap.

[0016]FIG. 7 is the same as the preceding Figure, except that thecartridge is shown totally engaged on its support after percussion ofits cap.

[0017] Referring to the Figures, the cryotherapy apparatus 1 which willbe described by way of non-limiting example is particularly intended forso-called domestic use, i.e. by a user who is in principle not aprofessional.

[0018] In this respect, FIG. 1 shows a general view of the apparatus 1grasped in a user's right hand 2 with a view to an application on theepidermis 3 of a region to be treated of a gas under pressure—preferablycarbonic anhydride (CO2)-, in at least partially solid phase coming froma disposable or re-usable cartridge 4, which is screwed, with its headdown, in a cartridge support provided in the upper part of the apparatus1 in order to maintain and strike an opening cap placing the contents ofthe cartridge 4 in contact with the cryogenic chain which will bedescribed hereinbelow. For safety reasons, the projection of the gas onthe epidermis 3 is controlled by the simultaneous action of a firstswitch 5 controlled by the thumb of the hand 2 and of a second switch 6preferably having the form of a push-trigger 6 disposed in the region ofthe index finger of the hand 2 when the apparatus is grasped in the handas represented in FIG. 1.

[0019] The CO2 in liquid/solid phase 7 is ejected via a calibratedopening 8 which will be specified hereinbelow, located in the lower partof the apparatus and substantially in its vertical axis. For reasons ofsafety and in particular in order to avoid the temperature of theepidermis 3 under treatment passing below the critical temperature of 0°C. which creates a risk of necrosis of the epidermis, it is necessary toprovide a minimum distance between the outlet 8 of the gas and theepidermis 3 to be treated. To that end, there is provided an excrescencein the form of a prop 9 which extends downwardly substantially in theaxis of the apparatus 1 over a sufficient length to procure a suitablespacing between the outlet 8 and the epidermis 3, preventing a criticalvalue of temperature, fixed for example at 2° C., from being attainedwhen all the gas contained in the cartridge 4 is sprayed. It should benoted that the end of the prop 9 advantageously presents a shoe 10making it possible to distribute the pressure of the apparatus over thepatient's epidermis and to avoid injuring it during the treatment; inaddition, the prop 9 is advantageously located on the proximal side ofthe apparatus, i.e. towards the user's arm, allowing him/her to bettervisualize the zone of treatment during the whole projection.

[0020] In accordance with an essential configuration of the apparatus 1according to the invention, the cryogenic chain shown in FIG. 2 isdisposed substantially in line and in its axis, inside an ergonomichousing 11 of which the median part 12 (FIG. 1) serves as handle to begrasped by the adult user's hand; preferably, the median part 12 of thehousing 11 is in fact substantially convex on the proximal side (i.e.towards the arm of the user), in order to follow the curvature of histhumb; in addition, a recess 13 in the upper part of this side of thehousing 11 allows a movement of approach and of pivoting of the user'sthumb to actuates control of the apparatus as will be stated hereinafterwithout interrupting the contact of the base of the thumb with thehousing 11; on the distal side (i.e. the side most remote from theuser), the median part of the housing is substantially concave in orderto ensure complete grasp by the other four fingers, thus procuring agood grip of the apparatus 1 by one hand 2 of the adult user and to makeit possible, by one or the other of his four fingers, to actuate at thesame time the trigger 6 in order to control projection of gas 7.

[0021] According to a preferred embodiment of the apparatus 1, thehousing 11 is preferably constituted by two half-shells 14, 14′ ofidentical shape, assembled against one another in the median verticalplane of the housing 11. The general shape of each half-shell 14, 14′ isrepresented in plan in FIG. 2, on the inner side of the housing 11; theouter shape of each half-shell 14, 14′ is shown in front view in FIG. 1and in side views in FIG. 4 for the proximal view and in FIG. 5 for thedistal view.

[0022] According to an important arrangement of the apparatus inaccordance with the invention, the median part 12 of the housingconstituting the member for gripping the apparatus, has a mean sectionsuch that it fits perfectly in an adult's hand but that, reciprocally,it is difficult to hold in a child's hand; in this way, the latter willhave difficulties in holding the apparatus in one hand, which, inaddition to the electrical safety means which will be specifiedhereinbelow, constitutes a determining element for the safety ofchildren.

[0023] With reference to FIGS. 2 and 3, the cryogenic chain of theapparatus 1 will now be specified, disposed substantially in line in theaxis of said apparatus, and maintained in correct position thanks tohousings provided inside the half-shells 14 and 14′ in which each of theelements constituting the chain fits precisely with the result that,after the two half-shells 14, 14′ are assembled, the assembly is totallyrigid.

[0024] The cryogenic chain successively comprises, in the upper part ofthe apparatus 1, a support 20 receiving, on the upper side, the drawingoff head 21 of the cartridge 4 via a nut 22 forming connecting pieceand, on the other side, a nut 23 supporting a filter which will bespecified hereinbelow, an in-line electrovalve 24 intended to place thegas in its liquid form coming from the cartridge 4 in communication withthe gas ejection and expansion system constituted by a tube 25 of smallinner diameter of the order of 0.5 mm. In accordance with an importantcharacteristic of the apparatus 1 according to the invention, it isprovided, for questions of safety already taken up in the preamble, tomonitor the sprayed gas thermally; to that end, the tube 25 of theejection and expansion system is associated with a cylindro-conicalsleeve 26 shown in FIG. 2 torn away on a larger scale; the sleeve 26 ismounted coaxially thanks to a radial wedging formed by at least threefins so that the cylindrical part 27 having an inner diameter greaterthan the tube 25, creates an air passage around said tube 25; the apexof the truncated part 28, extending the cylindrical part 27 downwardly,comes flush with the end of the tube 25 forming the gas ejection nozzle29, making an annular space 30 for the passage of air clearly smallerthan in the cylindrical part 27 in order to create by VENTURI effect anaspiration of the ambient air through holes 31 made at the base of thehousing 11 in order to limit in this way the temperature and thepressure in the region of the epidermis 3 to be treated.

[0025] According to another embodiment of the invention, it is alsopossible to monitor the outlet temperature and pressure of the gasejection and expansion system by giving the calibrated opening 8 in thelower part of the housing 11 a general nozzle shape, for example intulip form flaring in the direction of the nozzle 29 and disposed in thesame axis, at a correct distance in order to mix the ambient air suckedthrough the holes 31 by VENTURI effect generated by the propulsion ofthe gas.

[0026] It goes without saying that the two thermal regulation systemswhich have just been described may be combined in order to adjust thetemperature and pressure of the sprayed gas 7 even more finely.

[0027] The members constituting the cryogenic chain inside the apparatuswill now be described in detail, and this with reference to FIGS. 2, 6and 7.

[0028] The cartridge 4 of CO2, medicalized as the case may be, andliquefied under a pressure of about 50 bars is in fact a cartridgeconventionally comprising a metal recipient of cylindrical shape, closedat one end, quite similar to but smaller than the cartridges used inprior Patent FR 2 775 589 already cited; at the other end, the cartridgeis provided with a drawing off head 21 arranged to cooperate with asupport for use 20. The drawing off head 21 is constituted by anexternally threaded cylindrical connector, a cap 401 which is intendedto close the cartridge before it is placed in position in the apparatus,and an internally and externally threaded nut 22, the internal thread ofthe nut 22 being screwed on the thread of the connector of the drawingoff head 21 in order to maintain the cap 401 in place. The cartridge 4is in principle disposable taking into account its particular use, butmight also be refilled if necessary; the cartridges contain CO2 in aquantity sufficient for a treatment of about 15 seconds. The drawing offsystem comprises, as in the prior art, a system for automatic percussionof the cartridge, ensuring the necessary tightness during and after theperforation of the cap 401 for example made of bronze, obturating thecartridge 4. Similarly, the screw pitch of the nut 22 which is screwedabove the drawing off head 21 of the cartridge 4 has been voluntarilychosen from little used pitches so that it is not possible to usecartridges which are not in conformity.

[0029] The system of percussion of the cartridges 4 is composed of threeparts in accordance with FIGS. 6 and 7. A cylindrical support 20comprising on the cartridge side a first internally threaded inletchamber 201 in which is screwed the nut 22 previously mounted on thedrawing off head 21 obturated by the bronze cap 401; in the axis of thisfirst chamber 201 and opening thereinto, a second chamber 202, ofsmaller diameter, collaborates with the end 221 of the nut 22 ofdiameter smaller than the threaded part of said nut in order to ensuretotal tightness, thanks to an outer O-ring 222 mounted in the areaaround said end 221, between the cartridge 4 and the rest of the device,as soon as the striker 35 perforates the cap 401. The striker 35 formingthe second part of the system is constituted by a point 36 and is fastwith the support 20 which may engage in the hollow end part 223 of thenut 22 surrounding the drawing off head 21 until it comes into contactwith the cap 401 when the engagement of said nut 22 in the support 20 issufficient to ensure connection of the assembly; at that instant, thepoint 36 is in contact with the cap 401 and the O-ring 222 is in contactwith the walls of the chamber 202 ensuring its tightness with thedrawing off head 21; it then suffices, as shown in FIG. 7, to continueto screw the cartridge 4/nut 22 assembly inside the support 20 in orderto perforate the cap 401; the CO2 can then expand towards the downstreampart of the support 20, passing firstly through a longitudinal channel37 provided to that end in the axis of the striker 35 which opens out ina third coaxial chamber 203 of the support 20 necessary for positioningthe percussion system and supporting in the flow of the liquid CO2 afilter 38 intended to retain possible residues contained in thecartridge 4. The filter 38 is capped by a nut 23 cooperating with aninternal thread of the chamber 203 in conventional manner. The nut 23 isaxially traversed by a channel 231 and it is provided on its downstreamface with a threaded axis making it possible subsequently to implant theinput of the electrovalve 24.

[0030] The latter, chosen from high-pressure electrovalves, allows theopening and closure of an axial channel extending the preceding channel231 by simple control of an electromagnet disposed in the axis of theelectrovalve. At the output of the electrovalve 24, is mounted theexpansion tube 25 extending, if necessary, in the cylindrico-conicalsleeve 27 thermally monitoring the flux of CO2. It will also be notedthat, up to the outlet of the electrovalve 24, the CO2 is always in itsliquid form and there is therefore no formation of solid carbon dioxidecapable of preventing the circulation of the fluid; for the purpose ofregulating the outlet flowrate of the liquid CO2, the expansion tube 25is given a very small internal diameter, of the order of 0.5 mm; inorder to avoid the formation of a plug of ice at the outlet of theexpansion tube, a tube made of PTFE is preferably used and, taking intoaccount the pressure of the CO2 of the order of 50 bars at the outlet ofthe cartridge 4, the speed of flow of the CO2 inside the tube 25 issufficiently high to evacuate to the outside the solid carbon dioxide inmicronized particles.

[0031] When the cartridge 4 has delivered all its contents in liquidphase, it is necessary to proceed with its replacement or, in accordancewith another embodiment, with its refill. To that end, the cartridge 4should be withdrawn from its support 20 and the problem is then raisedof previously evacuating the residual gas inside the cartridge before itis completely withdrawn, in order to avoid a sudden recoil which may, inaddition, be accompanied by a detonation. In order to bleed thecartridge before its withdrawal, there is therefore provided a bleedhole 40 connecting the outside of the chamber 202 disposed most upstreamof the support 20, (i.e. the chamber not comprising the percussionmember 35). This bleed hole 40 (FIG. 6) ensures the bleed of theresidual gas at the moment of withdrawal of the cartridge 4 byunscrewing the nut 22 from its housing in the chamber 201 of the support20; naturally, the internal geometry of this chamber 201 has beenprovided so that, as soon as the uncapped head of the cartridge 4 isdisengaged from the percussion point 36, the residual gas is in contactwith the bleed hole 40, i.e. with the outside, while the length of thethread of the nut 22 still engaged in the chamber 201 is stillsufficient to maintain the assembly rigidly and to avoid any suddenrecoil of the cartridge released from its support; it will thereforesuffice, as soon as the hiss of the gas through the bleed hole 40 isheard, to wait for it to stop before continuing to unscrew the nut 22and remove the cartridge 4, with a view to replacing it, without danger.

[0032] According to a particularly important characteristic concerningthe safety of the apparatus, the electrovalve 24 supplied by batteries41 advantageously disposed in a housing 42 (FIGS. 3 and 5) in the upperpart of the distal face of the housing 11 (FIG. 5) and controlled, i.e.switched on, by the simultaneous pressing of the two switches 5 and 6mounted in series in the electrical supply, i.e. between the batteries41 and the coil of the electrovalve 24; as has already been stated, andin order to avoid any manipulation, particularly by children, therelative position of the two switches 5 and 6 projecting on the housing11 is such that, when the median part of said housing is in an adult'shand, the first switch 5, preferably in the form of a push button, comessubstantially under the user's thumb and the second switch 6,advantageously in the form of a trigger, can be actuated by at least oneof the other four fingers of the hand. It has been seen that the twoswitches 5 and 6 were, to that end, located respectively on either sideof the housing 11, diametrally opposite in its median plane.

[0033] According to a final characteristic of the invention, theapparatus 1 which has just been described may advantageously becompleted by a complementary member for monitoring the temperature ofthe zone of use in order to avoid the drop in temperature favourable forthe treatment causing necroses of the tissues; to that end, andaccording to a particular embodiment of the invention, it is provided toadd a temperature threshold detector 45 coupled to control electronicsand capable of functioning remotely without contact with the zone of useor of care, in accordance with FIGS. 2 and 3. Placed in the lower partof the housing 11 for the optics of the detector 45 to be centred in thedirection of the zone to be treated, the preferred temperature thresholddetector has been chosen as an infra-red pyrometer preferably operatingwith a D.C. supply of 12 volts like the electrovalve 24; in practice,the focal distance of the optics of the pyrometer 45 is chosen so thatthe field of vision corresponds as completely as possible to the targetto be measured on the epidermis in order to obtain a correct and precisetemperature reading. To that end, the position of the pyrometer 45 iscalculated precisely in order that its distance to the zone of treatmentnot be either too short, as in that case the heat gradient of the skinbecomes so great that the temperature of the treated zone and thetemperature of the zone scrutinized by the pyrometer are very far fromeach other, with the consequence of rendering the alarm order random,nor be too far, which would almost surely lead to a superpositionbetween the jet of solid carbon dioxide and the infra-red radiation,with the consequence that the pyrometer would read the temperature ofthe jet more surely than that of the zone to be supervised.

[0034] According to an accessory characteristic, the threshold detectorof the pyrometer 45 is regulated to a temperature of the order of 5° C.in order to conserve a safety margin; according to a first embodiment,when the temperature threshold of the pyrometer 45 is attained, thecontrol electronics which are associated therewith warn the user by asound or visual signal and/or may cut off the supply of the electrovalve24, suddenly stopping the projection of the CO2; according to anotherembodiment, the pyrometer 45 can send a sound or visual signal when afirst danger threshold is attained and cut off the electrovalve 24 whena second threshold is attained, for example around 2° C.

[0035] The apparatus 1 according to the invention, in accordance withone or the other of the embodiments which have just been described, maybe used simply by any adult, non-professional user. To that end, it willsuffice for him to grip in his right hand, for example, the median part12 of the housing 11 of the apparatus, to introduce in the upper partthereof a new cartridge 4 and screw it in its support 20 untilpercussion of its cap 401 is obtained; the apparatus is then ready tooperate and it will suffice for the adult user to bring it towards theepidermis 3 on which it is desired to effect a cryotherapy, maintainingit vertically until the end 10 of the prop 9 is in contact with the zoneto be treated; at that moment, and the apparatus being maintainedvertically, it will suffice for the user to press simultaneously on thebutton 5 with his thumb and on the trigger 6 with his index finger inorder to trigger off the electrovalve 24 and therefore the projection 7of a flow of CO2 in liquid/solid phase. In principle, the cartridge ofthe apparatus is provided for one operation, i.e. to take the zone to betreated from a temperature of about 32° C. to a temperature includedbetween 2 and 5° C., and this in about 15 seconds. The thermal safetyarrangements of the apparatus have already been seen hereinabove but itwill nonetheless be observed that, when the apparatus is poorlypositioned, voluntarily or not, i.e. when it is no longer in thevertical axis allowing the prop 9 to perform its role of separatorfully, the diameter of the cartridge 4 is such that, very rapidly, theflow propelled via the nozzle 29 of the ejection and expansion system isin fact in gaseous form therefore without danger for the epidermis fromthe thermal point of view.

[0036] Finally, in accordance with a simpler embodiment of the apparatusaccording to the invention, it is possible to replace the electrovalve24 and all its electrical controls by a purely mechanical device of themanually actuated mechanical valve type. This embodiment, not shown inthe Figures, consists in replacing the electrovalve in the line of thecold by a transverse piston valve actuated by a lever arranged in thezone of grip of the body of the apparatus; in this way it suffices totighten the trigger arranged within reach of the hand holding theapparatus in order to actuate the piston valve, which is, in fact, thesame as placing in contact, upstream, the drawing off head of thecartridge 4 and, downstream, the liquefied gas expansion and ejectionsystem.

[0037] In this simplified version of the apparatus, it goes withoutsaying that the drawing off head of the cartridge may advantageously beobtained by a contraction of the end of the envelope of the cartridgeprovided with an adequate thread screwing directly in the cartridgesupport 20 comprising, as in the preceding variant, a percussion member35; the cartridge thus simplified is obviously provided with a capcooperating with said percussion member, as in the preceding variant.

[0038] In this embodiment, a detector of temperature of the zone to betreated is not necessarily provided, insofar as the quantity of gascontained in the cartridge in its simplified version is such that it isnot possible to descend this side of the critical temperature even whenthe contents of this cartridge are totally ejected.

[0039] According to another arrangement which, moreover, is applicableto all the variants of the apparatus according to the invention, theprop 9 making it possible to arrange the nozzle 29 of the ejectionsystem at the correct distance, may be replaced by a hollowed base ofcylindrical, truncated cone or truncated pyramid shape, issing from thelower part of the housing 11 and extending downwardly substantially inthe axis of said housing over a determined length in order to ensure asufficient safety distance as explained hereinabove concerning the prop9. This hollow base device presents, furthermore, the advantage of abetter stability of the apparatus at rest and it naturally avoids anyerror of positioning of the apparatus above the zone of the epidermis tobe treated.

[0040] Functioning of the apparatus in its simplified mechanical versionis extremely simple, which renders it particularly suitable for generalpublic use.

1. Self-contained cryotherapy apparatus adapted to be manipulated withone hand, using the expansion temperature and pressure of a liquefiedgas sprayed in at least partially solid phase on a human or animalepidermis (3), such as CO2 or equivalent, contained under pressure in aremovable cartridge (4), of which the drawing off head (21), which isconnected by a support (20) to a controlled system of ejection and ofexpansion of the liquefied gas, is such that, for the whole duration ofa projection, only the liquid part of the gas inside the cartridge comesinto contact with said drawing off head, characterized in that thesupport (20) of the cartridge and the controlled ejection and expansionsystem are disposed substantially in line and in the axis of theapparatus, inside an ergonomic housing (11) whose axis corresponds tothat of the apparatus, of which the median part serves as handle to begrasped by the adult user's hand (2) and comprises the member forcontrolling the controlled gas ejection and expansion system of whichthe upper part presents an inlet for introducing into its support thecartridge (4), head down and in the axis of the housing (11), and forstriking it or for withdrawing it after use, and of which the lower partcomprises a calibrated opening (8) forming a passage for the sprayed gassubstantially in the axis of the housing and means (9) for holding theoutlet nozzle (29) of the controlled ejection and expansion system atthe required distance with respect to the zone of the epidermis to betreated.
 2. Apparatus according to the preceding claim, characterized inthat the controlled ejection and expansion system comprises anelectrovalve (24) in line with a tube (25) for ejection of the liquefiedgas.
 3. Apparatus according to claim 2, characterized in that the memberfor controlling opening of the electrovalve (24) is constituted by twoswitches (5, 6) adapted to be actuated by the user's hand (2) andmounted in series in the electrical supply (41) of the electrovalve(24), the actuation of the electrovalve necessitating the simultaneouspressing of the two switches (5, 6) by the user's hand (2).
 4. Apparatusaccording to claim 3, characterized in that the relative position of thetwo switches (5, 6) projecting on the housing (11) is such that, whenthe median part (12) of said housing is in an adult's hand (2), thefirst switch, for example in the form of a push button (5), comessubstantially under the user's thumb and the second switch,advantageously in the form of a trigger (6), can be actuated by one ormore of the other four fingers of the hand (2).
 5. Apparatus accordingto claim 4, characterized in that the median part (12) of the housing(11) is shaped in order to be grasped by an adult user's hand, i.e.substantially convex on the proximal side in order to follow thecurvature of the thumb, a recess (13) in the upper part of the housing(11) allowing the movement of approach of the thumb without interruptingthe contact of its base with the housing, and substantially concave onthe distal side for a complete grasp of the other fingers.
 6. Apparatusaccording to claim 1, characterized in that the controlled ejection andexpansion system comprises a manual valve for example with pistondisposed transversely to the axis of the apparatus, coupled, upstream,to the drawing off head of the cartridge (21) and, downstream, to theliquefied gas expansion and ejection system.
 7. Apparatus according toany one of Clams 2 to 6, characterized in that the tube (25) of theliquefied gas ejection and expansion system is a tube of small innerdiameter, of the order of 0.5 mm.
 8. Apparatus according to any one ofthe preceding claims, characterized in that the means for holding thenozzle (29) of the ejection system at the required distance from theepidermis (3) to be treated are constituted by an excrescence of theprop (9) type or a recessed base of cylindrical, truncated cone,truncated pyramid shape provided to broadly cover the zone to betreated, issuing from the lower part of the housing (11) and extendingdownwardly, substantially parallel to the axis of said housing over adetermined length in order to maintain the required distance, when theapparatus (1) is positioned opposite the epidermis (3).
 9. Apparatusaccording to any one of the preceding claims, characterized in that thecartridge (4) comprises a tubular body closed at one end and presentingat the other end a drawing off head (21) constituted by an externallythreaded cylindrical connector, by a cap (401) which is intended toclose the cartridge before it is placed in position in the apparatus.10. Apparatus according to claim 9 with any one of claims 1 to 5, 7, 8,characterized in that the drawing off head (21) of the cartridge isprovided with an internally and externally threaded nut (22), the innerthread of the nut (22) being screwed on the thread of the connector ofthe drawing off head (21) in order to hold the cap (401) in place. 11.Apparatus according to one or the other of claims 9 to 10, characterizedin that the cartridge (4) is connected to the cartridge support (20) inthe apparatus by screwing so as firstly to bring the cap (401) intocontact with an advantageously fixed percussion member (35), extendingin the axis of the support (10), then to pierce said cap (401) ensuringtightness of the assembly in order to draw off the gas in liquid phasevia an axial channel (37) traversing right through the percussiondevice, connected downstream at its free end to the controlled expansionsystem, a bleed hole (40) between the inner space of the support (20)and the outside being provided radially in that part of said support(20) not comprising the percussion member (35) in order to bleed theresidual gas in the empty cartridge during its unscrewing and before itis completely disconnected from the apparatus.
 12. Apparatus accordingto any one of the preceding claims, characterized in that it comprisesmeans for monitoring the projected gas which consist in surrounding theoutlet tube (25) of the ejection and expansion system by acylindrico-conical sleeve (26) mounted coaxially thanks to a radialwedge of which the cylindrical part (27) has an inner diameter largerthan the tube (25) in order to create a passage of air all around saidtube and of which the apex of the truncated part (28) extending thecylindrical part (27) comes flush with the end of the tube (25) formingthe ejection nozzle (29) arranging an annular space for the passage ofair clearly smaller than in the cylindrical part (27) in order to createby VENTURI effect a suction of the ambient air through openings (31)made at the base of the housing (11) and thus to limit the temperatureand pressure in the region to be treated.
 13. Apparatus according to anyone of the preceding claims, characterized in that it comprises meansfor monitoring the projected gas constituted by the arrangement of thecalibrated opening (8) in the lower part of the housing (11) having thegeneral shape of a nozzle in the form of a tulip flared in the directionof the nozzle (29) of the tube (25) and is disposed in the same axis, atthe correct distance from said nozzle and via openings (31) made at thebase of the housing (11) so as to mix with the liquefied gas in thecourse of expansion of the ambient air sucked through openings (31) byVENTURI effect created by the propulsion of the gas.
 14. Apparatusaccording to any one of the preceding claims, characterized in that itcomprises a means for thermally monitoring the epidermis (3) which is adetector (45) for detecting the temperature of the epidermis (3) actingwithout contact therewith.
 15. Apparatus according to claim 14,characterized in that the detector is an infrared pyrometer (45). 16.Apparatus according to claim 15, characterized in that the focaldistance of the infrared pyrometer (45) is such, on the one hand, thatthere is no interaction with the spraying of the liquefied gas, and, onthe other hand, that the precise measurement of temperature is effectedwhen the apparatus (1) is positioned at a suitable distance for the useenvisaged.
 17. Apparatus according to either one of claims 15 or 16,characterized in that the infrared pyrometer (45) is coupled to a visualand/or sound alarm when the drop in temperature of the zone of usereaches a predetermined threshold, the pyrometer (45) in that case beingable, advantageously but not necessarily, to automatically cut off theelectrical supply of the electrovalve (24).